Grub

GRUB: GRand Unified Bootloader
Grub and Windows XP
Grub and Windows 10
Grub manual
Grub kernel parameters

Tool

grub-customizer is a tool to configure GRUB. It can be installed with aptitude
Grub tune tester on Github

Change default settings

Edit /etc/default/grub to your needs
Run update-grub when done

Parameters

Name	Explanation
GRUB_CMDLINE_LINUX	These options are always effective
GRUB_CMDLINE_LINUX_DEFAULT	These options are only effective during normal boot. Not during recovery mode
Options
quiet	Do not show verbose text during boot. This is the default. Can be omitted
verbose	Show verbose text during boot. Can be omitted
splash	Shows the splash screen. If omitted the splash screen does not show up. Can be omitted
pci=noaer	No pci advanced error reporting. Can be omitted
pci=nomsi	No system wide message signaled interrupts. Use only for debugging
intel_idle.max_cstate=x	This is the new way. Limit the maximum C state allowed to x. See also our System freeze page
processor.max_cstate=x	This is the old ACPI way. If possible do not use it, use: intel_idle.max_cstate
Sound
GRUB_INIT_TUNE=“t n[p d]“	Syntax: GRUB_INIT_TUNE=“tempo pitch (in Hz) duration (in seconds). Pitch and duration can be repeated in pairs. Example: GRUB_INIT_TUNE=“1480 660 1 440 3 770 2”. A collection of examples

GRUB commands

Have a look at these commands

grub-bin2h
grub-install
grub-mkconfig -o /boot/grub/grub.cfg
grub-mkimage
grub-mkpasswd-pbkdf2
grub-mount
grub-reboot
grub-setup
grub-editenv
grub-kbdcomp
grub-mkdevicemap
grub-mklayout
grub-mkrelpath
grub-ntldr-img
grub-script-check
grub-fstest
grub-menulst2cfg
grub-mkfont
grub-mknetdir
grub-mkrescue
grub-probe
grub-set-default
update-grub

grub bootscreen commands

To enter the editor press e
When finished press F10

echo text
sleep 20

grub rescue cli commands

See GRUB rescue shell: The “GRUB rescue >” prompt

insmod normal.mod
ls
set

grub troubleshooting

OS prober

This is important if other operating systems like Windows must be able to be booted

Warning: os-prober will not be executed to detect other bootable partitions.
Systems on them will not be added to the GRUB boot configuration.
Check GRUB_DISABLE_OS_PROBER documentation entry.

Solution: as root, in /etc/default/grub uncomment the GRUB_DISABLE_OS_PROBER line and set this variable to false. Doing so and running update-grub will detect other operating systems if present

Work in progress

update-grub issues

Although booting from the right partition, setting /etc/default/grub right and running update-grub, after a reboot the /boot/grub/grub.cfg file and thereby the presented grub menu does not represent what is expected from running the update-grub command
The expected partition is not the default partition on the top of the menu nor is grub started from the right partition

Grub rescue prompt

When the grub rescue> prompt appears with the message error: file '/boot/grub/i386-pc/normal.mod' not found.

Do set. Check if prefix, cmdpath and root are all on the same, right, drive
Continue with the next chapter

Resurecting the MBR

Boot with the Super grub 2 disk
Run grub-mkconfig
Run grub-install --target=i386-pc /dev/sdx (where x is the letter off the drive where the Linux installation is on
Run update-grub
Reboot

Check /boot/grub/load.cfg for the the right uuid. Also /boot/grub/i386-pc/load.cfg if applicable

Uninstall grub with aptitude
- remove grub
- update the package list
- Do U and g to check if anything else can be uninstalled
remove /boot/grub
remove /var/lib/os-prober if applicable
Reboot
Boot with Super grub 2 disk
Install grub2
Reboot
Run grub-mkconfig
Run grub-install /dev/sdx
Eject the Super grub 2 disk cd
Reboot

Remove Grub2 and install Grub Legacy

Boot issues

If Grub does not start / the computer boots in an OS by passing Grub then:

Download Super Grub2 Disk
Run Super Grub2 Disk on the computer
Boot into the preferred Linux installation
In the preferred OS do CTRL-ALT-F2
Login as root
Run install-grub /dev/sdX (not /dev/sdX1 !) X points to the drive Grub has to be installed on
Reboot
The computer now should run Grub on startup

Useful links

How to install the GRUB customizer on Debian
Install the GRUB customizer on Ubuntu 18-04 LTS

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